http://www.juniper.net/techpubs/en_US/junos/topics/concept/issu-oveview.html The Juniper ISSU guide. You need two things: 1. Separation of the control plane and forwarding plane 2. 2 routing engines in the same chassis -- the non active RE upgrades first, then when its up and running the active one goes into upgrade mode and control fails over to the secondary RE which is running the upgraded version of the software. I assume it works on any vendor that has 2 REs in the same chassis and the fwd and control planes are separated, and there is a redundancy protocol running between the two REs(like Graceful Switchover on Juniper gear). On 11/09/2012 01:42 AM, Kenneth McRae wrote:
Juniper also offers it on the EX virtual switching platform. Works if you have the correct version of JunOS.
On Thu, Nov 8, 2012 at 3:38 PM, Zaid Ali <zaid@zaidali.com> wrote:
Cisco Nexus platform does it pretty well so they have achieved it.
Zaid
On Nov 8, 2012, at 3:22 PM, Kasper Adel wrote:
Hello,
We've been hearing about ISSU for so many years and i didnt hear that any vendor was able to achieve it yet.
What is the technical reason behind that?
If i understand correctly, the way it will be done would be simply to have extra ASICs/HW to be able to build dual circuits accessing the same memory, and gracefully switch from one to another. Is that right?
Thanks, Kim